Any of Tippmann A5, 98, or SP Ion or SP8 will be fine for the woods and scenario play.
There all good, and all have lots of upgrades either internal or external.
If you're looking at the £70-£100 range, unless you are going second hand, then out of those 4 the only one you're likely to be able to pick up new for that price is the Tippmann 98